A floor covering for use as an entrance mat needs a heavily textured upwardly facing surface having wiper regions to remove dirt and moisture from footwear and recess regions to receive collected dirt pending periodic cleaning. One such type of floor covering in the form of an entrance mat is described in the assignees Patent Specification GB-A-2258624A. The mat comprises a plurality of first, spacer strips of substantially rigid material, for example of aluminum or a plastics material such as polyvinyl chloride or polypropylene, and a plurality of second, tread strips of substantially resilient and flexible material such as natural or synthetic rubber and which support a fibrous tread surface, the tread strips being interposed alternately between the spacer strips. The tread and spacer strips are secured together in side-by-side relationship by means of one or more connecting elements, such as wires, which pass through aligned apertures in the strips.
In the aforedescribed construction the fibrous tread surfaces of the tread strips serve primarily as wiper regions to support footwear passing thereover and perform a cleaning action whereas the recess regions provided by the spacer strips between respective neighbouring pairs of tread strips serve as collector grooves in which dirt may gather for subsequent removal during a mat cleaning operation.
Commonly the substantially rigid spacer strips are of an H-shape in cross-section with the cross piece of the H, in use, lying vertically in the direction of the thickness of the matting. Said cross piece is provided with apertures through which the connecting elements pass, and the edges of the side pieces of the H formation abut adjacent tread strips. Alternatively they are commonly of half an H shape, i.e. a C type shape as described in our Patent Specification GB-A-2090128A.
Conventionally each tread strip has an embedded reinforcement of one or more layers of fabric arranged to lie substantially transverse to the plane of the mat. The surface of the rubber or like substantially resilient material is removed from a face of the strip which is to define the tread surface so as to expose the fibres and provide a fibrous tread surface. The embedded reinforcement provides the strip with a good degree of stiffness so that it resists deformation when subject to load.
The resulting mat with a fibrous tread surface as descried in the preceding paragraph is found to exhibit excellent wear characteristics even in conditions of arduous use, and to remain effective in providing a cleaning action. However although the construction of the tread strips with an embedded reinforcement contributes to excellent wear characteristics, that material is expensive.
In some installations at which an entrance mat normally will be exposed to only lightly soiled footwear it may be acceptable to provide that the proportion of the mat surface which is comprised by the tread strips is less than usual and thereby reduce the proportion of the relatively expensive tread strips.
Theoretically the proportion of surface area comprised by the tread strips could be reduced by reducing the width of each tread strip to less than is conventional. In practice, however, any significant reduction in width will result in the mat having an unsatisfactory feel when walked on. Also the machinery used to manufacture standard width strips would need modification to manufacture strips of a narrower width. In consequence the economies of scale would be diminished.
The proportion of the mat surface area comprised by the tread strips in theory might alternatively be reduced by increasing the width of the spacer strips. In practice, however, difficulties arise in producing an extruded strip of greater width without increasing its thickness. Also the visual appearance of the mat generally may suffer because of the presence of a greater proportion of area occupied by the spacer strips.